The present invention relates to a drilling assisting device for hand-guided drill, in particular for diamond drilling.
The drilling is a critical moment for the hand-guided drilling process. If the tool guidance through a bore hole is not correct, then due to rotation of the tool tip the tool can be broken. Damages to the outer surface of the tool are then unavoidable. Because of this, drilling assisting devices are utilized during drilling. They usually provide an additional support for the drilling device on the surface of the workpiece.
Drilling assisting devices are known in the art. The known drilling assisting devices include one or two supporting elements which are mounted by a clamping mounting on a clamping neck of the drill. The supporting element is provided with a supporting part at the side of the tool. It serves for supporting on the surface to be treated and concentrically surrounds the drilling tool. Moreover, the connecting part during wet drilling serves as a capture ring for cooling water which flows from the drilling location.
Known drilling assisting devices with a single supporting element have a disadvantage which is connected with their cylindrical form. In particular, the supporting part, when the drilling tool is not inserted, does not provide a clear orientation for the machine or drill axis. Drilling assisting devices with two supporting elements eliminate this disadvantage, however they are relatively inconvenient, since the supporting elements extend relatively wide in a lateral direction. The application of the pressure to the supporting part is performed through spiral springs which are supported before the supporting part and the clamping mounting, and during pressing of the drill relative to the drilling product they are compressed. Such spiral springs has a relatively steep characteristic, which is not favorable since in the case of great drilling depth, the pressing force applied by the operator increases over proportionally. The usable pressing path in these embodiments is shortened by the length of the compressed spring pack. With increasing the drilling depth, the supporting element extends behind the clamping ring and posses an obstacle to the operator during handling of the drill.